Pressure wounds such as decubitus ulcers, which are commonly known as pressure ulcers or bedsores, are lesions developed when a localized area of soft tissue is compressed between a bony prominence and an external surface for a prolonged period of time. Pressure ulcers may appear in various parts of the body, and their development is affected by a combination of factors such as unrelieved pressure, friction, shearing forces, humidity and temperature.
Currently, about 10%-15% of hospitalized patients are estimated to have bedsores at any one time (Source: Medicare website 2009). However, it is not only hospitalized patients who suffer from pressure wounds: for example, people confined to wheelchairs are prone to suffer from pressure wounds, especially in their pelvis, lower back and ankles. Although easily prevented and completely treatable if found early, bedsores are painful, and treatment is both difficult and expensive. In many cases bedsores can prove fatal—even under the auspices of medical care.
The most effective way of dealing with pressure wounds is to prevent them. Existing preventive solutions are either passive (e.g. various types of cushioning) or active.
Active preventative solutions include manual or automatic redistribution of pressure. The most common active preventive approach is to maintain a strict routine of relieving pressure from sensitive body areas of a patient every two to three hours or so. Such a routine may be maintained for patients under constant medical care however, it is a difficult, labor intensive and costly task which does not meet the needs of individuals not requiring ongoing supervision of a caretaker.
Another active preventative approach to bedsores includes using a dynamic mattress that alternately inflates and deflates air cells so as to redistribute supportive pressure upon the patient. However, such mattresses typically redistribute pressure in a patient independent manner, including from less sensitive regions thereby needlessly or even actually detrimentally creating higher pressure in sensitive areas.
The applicants' copending international patent application WO 2010/119441, which is incorporated herein by reference, discloses a pressure sensing system for use in preventing decubitus ulcers, or bedsores, which comprises a sensing-mat including a plurality of sensors configured to detect pressure applied to body parts of a subject resting on a surface such as a bed or a chair. Information received from the sensors is analyzed by the system, which further issues alerts according to sensor readings.
Obtaining accurate values from measurement sensors may be difficult. Moreover, measurements may take a significant amount of time, for example when it takes time for a sensor to stabilize into a resting position in response to pressure changes. Time elapsed from the moment a pressure change occurs until a stable sensor reading is reached may be critical in real-time scenarios. Belated sensor readings may prevent systems from issuing relevant alerts in a timely manner.
Although this problem may be circumvented using costly materials or technologies that are quick to respond to changes, such materials are expensive and often excessively susceptible to amortization. Thus integrating complex technologies may both increase the cost and reduce the durability of sensor-based systems.
It will be appreciated that there is therefore a need for a cost-effective, reliable method for obtaining accurate reading values from sensors in a timely manner. The systems and methods disclosed hereinbelow address this need.